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The Indian Pharmacopoeia Commission (IPC) in Ghaziabad, UP. The IPC has received 556 adverse reports this year. (Express Photo by Praveen Khanna)

Coronary stents manufactured by US healthcare major Abbott account for more than half of the adverse event reports in 2018 for medical devices. An adverse event report is the first stage to ascertain whether a device is defective and may eventually have to be recalled.

An analysis by the Indian Pharmacopoeia Commission shows they have received 290 adverse reports — of 556 reports logged so far this year — for devices manufactured by Abbott, and a vast majority are for its top selling Xience Prime, Xience Xpedition and Xience Alpine drug-eluting coronary stents.

Responding to queries from The Indian Express, a spokesperson for Abbott spokesperson said their Xience series of stents are recognised as the “gold standard and are among the world’s most used and studied stents with an unparalled safety record.” The company presently has around 40% of the cardiac stent market in India but did not provide precise sales figures.

Yet what can be a matter of concern, both for regulatory authorities and hospitals which have dispatched the adverse event reports, is the repetitive, if not identical, nature of the 30-odd cases that have been reaching the IPC every month from all parts of the country.

Consider these extracts from the adverse event reports:

July 23, 2018 at the Saraswati Heart Care Hospital in Allahabad. The report states an Abbott Xience Xpedition stent was implanted on a heavily calcified LAD (left anterior descending coronary artery). Subsequently, dissection was noted and another Xience Expedition stent was implanted. However, the patient expired. The cause of death was not provided by the hospital.

January 5, 2018 at the Holy Heart Advanced Cardiac Care & Research Center, Rohtak. The report states that a drug-eluting Xience Alpine Abbott stent was implanted on a patient, who had suffered a myocardial infarction (heart attack), with good results. About 30-40 minutes, post implantation, the patient experienced chest discomfort and an angiography showed thrombosis. Therefore, another Xience Alpine stent was deployed across the previously implanted stent to treat the thrombosis.

June 23, 2018 (name of hospital not given in report). An Abbott Xience Xpedition Stent Delivery System (SDS) was advanced in the LAD (left anterior descending) coronary artery of a 62-year old male patient and the stent implanted. Subsequently, a dissection was noted in the left main coronary artery and another Xience Xpedition stent was implanted to treat the dissection. But, the patient expired.

In case after case, there is mention of dissection and, in a few cases, stent thrombosis being noticed but the final conclusion in the reports varies from the “adverse event” either being caused or not caused by the device or that the investigation in the case was incomplete/the cause of death not provided.

In 13 cases of death in the 2018 reports, there is only one linked to a drug-eluting stent not manufactured by Abbott. And there is only one among the 12 cases reported for Abbott devices where there is a description that the patient took discharge from hospital against medical advice and passed away.

The fact that almost 300 such adverse events have been reported this year connected to devices manufactured by one company has not yet set off alarm bells among the authorities concerned.

Asked about this, Dr Vivekanandan Kalaiselvan, IPC’s Principal Scientific Officer, said the committee was being convened by them shortly. “The problem we are facing with adverse event reporting for devices is that information is often incomplete, and we have to revert to hospitals and our monitoring units to collect the missing information,” he said.

In response to queries on the repeated incidents of dissection being noted by cardiac surgeons, resulting mostly in a second stent being implanted, an Abbott spokesperson said that device-related dissections were “rare.”

“Abbott continuously monitors adverse events and provides information to all global health authorities including CDSCO as required. Device-related dissections are rare, with most dissections being related to severity of disease and how the device is delivered,” its spokesperson said.

But there are other key indications following the frequency of adverse event reporting on Abbott stents. One is that the reporting centres have fed in the batch number of the coronary stent responsible for the adverse event into VIPER (vascular integrated product experience and reporting software) and, in several cases found that there have been up to four similar incidents previously reported from the same batch of stents.

While Abbott, it is learnt, is yet to be contacted by either the CDSCO or the IPC on the frequency of the adverse event reporting in India, some of the reports themselves mention that hospitals have established contact with the company.

In one case, there is mention of the company being reached following a “suspect discrepancy” after a stent implantation and in another, that the errant stent had been returned to the company. There are several other cases where the “adverse event” reported is the description of how the Abbott stent “did not mitigate” and dozens of instances wherein “additional” Abbott stents were implanted after dissection was noticed.